Fabrication method of optical device having current blocking layer of buried ridge structure

Abstract

An optical device having a current blocking layer of a buried ridge structure and a fabrication method thereof are disclosed. This invention reduces a leakage current between active layer and ion implant layer in buried ridge structure. To minimize leakage current, a P-N-P current blocking layer and an ion implanting current blocking layer are combined. An optical device of the present invention includes: active layers of a mesa structure in a predetermined region on a substrate; a first current blocking layer of a P-N-P structure, which is placed to cover the mesa structure; and a second current blocking layer of a buried ridge structure, which is placed to surround the environs of the first current blocking layer.

What is claimed is:  
     
       1. A method for fabricating an optical device, comprising the steps of: 
       a) forming active layers of a mesa structure in a predetermined region on a substrate;  
       b) forming a first clad layer having a p-type along the surface of the active layers;  
       c) forming a second clad layer having a n-type on the first clad layer by using the favorable condition of predominant side growth;  
       d) exposing the first clad layer in the upper part of the active layers by etching the second clad layer;  
       e) forming and planarizing a first conductive third clad layer in the upper part of the whole structure completed with the above four steps; and  
       f) forming a current blocking layer by hydrogen ion implantation on the first clad layer and the second clad layer.  
     
     
       2. The method as recited in  claim 1 , wherein the step f) includes the steps of: 
       f1) forming a blocking mask for ion implantation which covers the active layers and the second clad layer; and  
       f2) performing hydrogen ion implantation by using the blocking mask for ion implantation.  
     
     
       3. The method as recited in  claim 1 , wherein the etching in the step d) is a wet etching.